Direction indicating and emergency switch device for automobiles

ABSTRACT

In a direction indicating and hazard flasher device for automobiles comprising a power source, indicator means, including two groups of lamp loads, direction indicator and hazard switches connecting the indicator means to the power source through switching means, the improvement wherein the switching means comprises a first contact connected between the direction indicator switch and the power source, a switch actuator being energized from the power source for periodically actuating the first contact, a series circuit of a second normally closed contact and a current winding, the series circuit being connected in parallel with the first contact, and a voltage winding connected in parallel with the second normally closed contact, the second normally closed contact being opened by the current winding only when a current larger than a predetermined value is carried therethrough to either one of the lamp loads and being held in the open state by the voltage winding in cooperation with the current winding, whereby the lamp load is not flashed if the current through the current winding is smaller than the predetermined value due to some failure thereof.

United States Patent Sakurai [451 Jan. 18, 1972 [72] Inventor: YasuhikoSakurai, Kariya-shi, Japan [73] Assignee: Nippon Denso KabushiltiKaisha, Kariyashi, Japan [22] Filed: Sept. 11, 1969 [2]] App]. No.:857,013

Primary Examiner-John W. Caldwell Assistant ExaminerKenneth N. LeimerAtt0rneyCushman, Darby & Cushman [57] ABSTRACT In a direction indicatingand hazard flasher device for automobiles comprising a power source,indicator means, including two groups of lamp loads, direction indicatorand hazard switches connecting the indicator means to the power sourcethrough switching means, the improvement wherein the switching meanscomprises a first contact connected between the direction'indicatorswitch and the power source, a switch actuator being energized from thepower source for periodically actuating the first contact, a seriescircuit of a second normally closed contact and a current winding, theseries circuit being connected in parallel with the first contact, and avoltage winding connected in parallel with the second normally closedcontact, the second normally closed contact being opened by the currentwinding only when a current larger than a predetermined value is carriedtherethrough to either one of the lamp loads and being held in the openstate by the voltage winding in cooperation with the current winding,whereby the lamp load is not flashed if the current through the currentwinding is smaller than the predetermined value due to some failurethereof.

2 Claims, 4 Drawing Figures Pmmmm: am: 3.83651 1 sum 1 or 3 INVENTORvasmko 50mm, BY [Em/2W? @zhman ATTORNEYS FIG 4 I NVENTOR fiSuH/Ko akwaBY M0 auhr m ATTORNEYS DIRECTION INDICATING AND EMERGENCY SWITCH DEVICEFOR AUTOMOBILES FIELD OF THE INVENTION This invention relates to animproved switch device in an automobile both for producing a directionindicating signal and for producing an emergency signal required whenthe au tomobile is stopped from running due to some fault or in similarcases.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a block diagram of theelectric circuit of the switch device of the above-described typeaccording to the prior art; and

FIG. 2 is a block diagram of the electrical circuit in the switch deviceaccording to a first embodiment of the present invention.

FIG. 3 is a block diagram showing the electrical circuit of the switchdevice according to a second embodiment of the present invention; and

FIG. 4 is a graph illustrating the voltage characteristic of the currentflowing in the ordinary electric lamps.

DESCRIPTION OF THE PRIOR ART As shown in FIG. 1, the conventional switchdevice comprises a switch actuator 6 driving a normally closed contact5, a normally open contact 9 and a current winding 8 for driving thecontact 9, so that only when the load current flowing in the winding 8is more than a predetermined value, the normally open contact 9 can beclosed to operate the switch actuator 6 and thereby flash a right-handgroup of direction indicator lights 1, I, 3 or a left-hand group ofdirection indicator lights, 2, 2, 4 depending on the position of thedirection switch 10. If one of the right-hand group of directionindicator lights 1, 1 3 or the left-hand group of direction indicatorlights 2, 2, 4 goes off by a fault, the load current is reduced tothereby cause the winding 8 to open the normally open contact 9 so thatthe switch actuator 6 is deenergized, thus indicating the failure of thesaid one direction indicator light. Also, in an emergency, an emergencyswitch I1 is closed to energize the switch actuator 6 and thereby tooperate the normally closed contact so that all the direction indicatorlights are flashed.

However, the above-described conventional device has a disadvantage thatthe magnetomotive force of the current winding 8 is affected by thetransient surge current which is several times as much as a steady-statecurrent which flows into the direction indicator lights immediatelyafter they are turned on and the winding 8 may close the normally opencontact 9 to cause the switch actuator 6 to operate even when one of thedirection indicator lights goes off. Especially in a threelight typedirection indicator device in which the group of direction indicatorlights on either side of the vehicle consists of three direction lightsas shown in FIG. I, the decrement of the load current caused by thefailure of one of the direction indicator lights is only one-third ofthe steady-state current, and this results in a disadvantage that thedetection of the failure of one of the direction indicator lightsbecomes very difficult because of the said surge current.

Another disadvantage peculiar to the foregoing prior art device arisesfrom the fact that the disconnection of one direction indicator light isdetected by the inactivation of the switch actuator 6 due to thedecrease in the load current flowing in the current winding 8. In anemergency where the emergency switch 11 must be closed so as to flashall of the direction indicator lights, if a less number of directionindicator lights than a predetermined number are lit due to the damageof some of these lights or for any other reason, the remaining sounddirection indicator lights will not be flashed and no emergency signalwill be produced. Thus, according to the prior art, the generation of anemergency signal is rendered unreliable in order to ensure the properfunction of detecting the failure of one of the direction indicatorlights.

Still another disadvantage existing in the prior art device involves thefollowing problem which occurs during the operation. Since the switchactuator 6 is connected with a power source 7 through the normallyclosed contact 5 and normally open contact 9, source voltage is appliedto the switch actuator 6 during the switching operation thereof when thenormally closed contact 5 is closed, and then the voltage drop sometimesbecomes too great to properly operate the switch actuator 6 itself.Especially during an emergency, as all the direction indicator lightsare brought into the load, the load is greatly increased, and this inturn causes a considerable drop of the voltage applied to the switchactuator 6, which might lead to the malfunction of the said actuator.

SUMMARY OF THE INVENTION It is an object of the present invention toeliminate the foregoing disadvantages, and for this purpose, in view ofthe fact that the surge current in electric lights diminishes shortlyafter they are turned on, to construct the detector circuit fordetecting the failure of the direction indicator lights in such a mannerthat the detector circuit is operated always after the directionindicator lights are turned on and always by a steadystate current in adirection indicator lights, thereby accomplishing the reliable detectionof the failure of one of the direction indicator lights withoutinfluence of the surge current and disconnecting the detector circuitfrom the power source during the while the emergency switch is closed,so that the direction indicator lights are assuredly flashed even if thenumber of the lights is decreased to one.

According to the present invention, the failure of one directionindicator light may be reliably detected without being affected by therush current and such detection is ensured over a wide voltage range ina three-light type direction indicator device. In addition to such anexcellent merit, there is provided another high merit that as a normallyclosed contact 11 can be opened with the closure of the emergency switch11 in an emergency the circuit constituted by a current winding 8 and avoltage winding 8' is disconnected from a power source 7 so as to enableall the direction indicator lights to be flashed regardless of number ofthe lights.

It is another object of the present invention to provide a directionindicating and emergency switch device for automobiles in which thedetector for detecting the failure of the direction indicator lights isarranged so as to be operated always after the direction indicatorlights are turned on and al' ways by a steady-state current to therebyenable the failure of one of the direction indicator lights to bereliably detected over a wide voltage range even in a three-light typedirection indicator device, and without suffering from any influence ofthe surge current. In such a switch device, the load interrupting switchis arranged to be driven by the source voltage during on-load periods tothereby ensure reliable operation even if the load of the power sourcebecomes great as in the case of an emergency.

According to the present invention, the detection of the failure of oneof the direction indicator lights may be reliably accomplished withoutinfluence of the rush current and such detection is possible over a widevoltage range even in a threelight type direction indicator device. Inaddition, power may be supplied to the switch actuator during the whilethe normally open contact for interrupting the load current is open orwhen no load is present, so that the switch actuator can drive thenormally open contact in its no-load condition, namely at a maximumsource voltage, thus ensuring the direction indicator lights to beflashed even if the load is very great as in the case of emergency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will nowbe described more fully with respect to the preferred embodimentsthereof shown in the accompanying drawings.

In a first embodiment shown in H6. 2, numerals 1 to 4 denote automobiledirection indicator lights, which consists of right-hand directionindicator lights 1, l, 3 and left-hand direction indicator lights 2, 2,4. Numeral 5 represents a normally closed contact actuated by a switchactuator 6, which may be of the type utilizing the charging anddischarging of a capacitor or the type utilizing the expansion andcontraction of a hot wire. Numeral 7 denotes a power source, 8 a currentwinding, and 8 a voltage winding. Both windings 8 and 8' are wound on acommon iron core so that their magnetomotive forces are added to eachother. Numeral 9 shows a normally closed contact driven by the windings8 and 8. These windings 8 and 8 together with the normally closedcontact 9 constitute a load detector 15. Numeral l denotes a directionindicator switch, 11 an emergency switch, 11 a normally closed contactto be opened with the closure of the emergency switch l1, 12 a powersource terminal, 13 a load terminal, and 14 a load current detectionterminal.

in operation, if, for example, the direction indicator switch 10 isleftwardly closed to effect the indication of a leftward turn of thevehicle, current flows into switch actuator 6 through the normallyclosed contact while current also flows into the left-hand directionindicator lights 2, 2', 4 which are turned on thereby. After apredetermined time the switch actuator 6 opens the normally closedcontact 5 and consequently, current flows in the circuit of winding 8through the normally closed contact 9, so that the normally closedcontact 9 is opened by the magnetomotive force of the winding 8. Afterthe contact 9 is opened, it is maintained open by the electromotiveforce of the windings 8 and 8 with the result that, the normally closedcontacts 5 and 9 now both being open, only small current flows throughthe current and voltage windings into the left-hand direction indicatorlights 2, 2, 4, but the lights are not lighted thereby. Subsequently,after a predetermined time, the switch actuator 6 closes the normallyclosed contact 5 to thereby turn on the left-hand direction indicatorlights 2, 2, 4 again. Concurrently therewith, the circuit of windings 8and 8 is short-circuited to allow the normally closed contact 9 to closeagain. These operations are repeated to alternately turn on and off theleft-hand direction indicator lights.

Description will now be made of the case where one of the left-handdirection indicator lights 2, 2, 4 is disconnected by a fault. With thedirection indicator switch closed leftwardly, the remaining sound onesof the left-hand direction indicator lights 2, 2, 4 are turned on whilethe actuator 6 opens the normally closed contact 5 after a predeterminedtime. This causes current to flow in the circuit of winding 8 andwinding 8', but the magnetomotive force of the current winding 8prevents the normally closed contact 9 from being opened because thecurrent flowing in the aforementioned circuit is reduced by the cutoffof one of the direction indicator lights. As a result, the normallyclosed contact 9 is maintained closed. Therefore, the remainingdirection indicator lights are kept turned on by the current passingthrough the normally closed contact 9 and current winding 8 even if thenormally closed contact 5 is open. Thus, the driver of the vehicle canrecognize the disconnection of one of the direction indicator lightsfrom the fact that an indicator lamp (not shown) located in the vehiclecabin and connected in parallel with the direction indicator lightsremains turned on.

The circuit of current winding 8 and voltage winding 8' is functionablealways after the normally closed contact 5 is opened, that is, after thedirection indicator lights are lit for a predetermined time. Therefore,at the point of time when the circuit starts operation, the temperatureof the direction indicator lights and therefore their resistance assumea substantially steady-state value. This means that a substantiallysteady-state current flows in the current winding 8 from the beginningto substantially prevent the direction indicator lights from beingaffected by the surge current flowing thereinto just after the lightsare turned on. Thus, the disconnection of one of the direction indicatorlights can be reliably detected in a three-light type directionindicator device according to the present invention.

With reference to FIG. 4, description will now be made of the detectionof the failure of the one of the direction indicator lights by thepresent invention in comparison with that by the prior art. in FIG. 4illustrating the voltage characteristic of the current flowing in theelectric lights, the vertical axis represents current I and thehorizontal axis voltage V. Letter A represents the current for one ofthe direction indicator lights, B the current for two of them, and C"the current for three of them. In the device according to the prior art,assume that 1,, is the minimum current value required for the normallyopen contact 9 to be closed by the magnetomotive force of the currentwinding 8 when all of the three direction lights are lit. Then theminimum current value required for the normally open contact 9 to beclosed by the magnetomotive force of the current winding 8 when one ofthe direction indicator lights goes off or when two of them are lit,assumes a value 1,, which is smaller than I This is because in orderthat the current may be l when one of the direction indicator lightsgoes off, the voltage must exceed V, which is the voltage when thecurrent is under the normal condition of the direction indicator lights,and this voltage increase causes the surge current appearing after theturn-on of the direction indicator lights to increase in accordance withthe voltage increment and thereby the current winding 8 closes thenormally open contact 9 even if the steady-state current is of a value1,, which is smaller than Therefore, in the three-light type directionindicator device according to the prior art, Z, is the operating voltagerange over which the cutoff of one of the direction indicator lights canbe detected.

in contrast, the device of the present invention is operated always bythe steady-state current of the direction indicator lights withoutinfluence of the surge current. Assuming that 1,, is the minimum currentvalue required for the normally closed contact 9 to be opened by themagnetomotive force of the current winding 8 under the normal conditionof the direction indicator lights, then the same minimum current 1,, isrequired for the normally closed contact 9 to be opened by themagnetomotive force of the current winding 8 even when one of thedirection indicator lights goes off. Thus, in the three-light typedirection indicator device of the present invention, the operatingvoltage range over which the failure of one of the direction indicatorlights can be detected is Z covering the voltage between V, and V Thisoperating voltage range Z is the maximum width determined by the voltagecharacteristic of the electric lights, which means that the deviceaccording to the present invention enables the failure of one of thelights to be detected over the theoretically greatest possible range. Inthis way, the present invention ensures the failure of one of thedirection indicator lights to be detected over a wide voltage rangepractically required in a three-light type direction indicator device.

If it is necessary to produce an emergency signal to prevent any dangerfrom taking place when the vehicle stops due to its trouble or insimilar cases, the emergency switch 11 (FIG. 2) is closed to connect allof the left-hand and right-hand direction indicator lights with the loadterminal 13 and to open the normally closed contact 11'. As a result,the circuit of current winding 8 and voltage winding 8' is disconnectedfrom the power source 7 and dissociated with the ON-OFF operation aswill be described. On the other hand, the switch actuator 6 operatesindependently of the magnitude of the load and therefore the directionindicator lights turn on and off at a predetermined number of intervalsirrespective of the number of such lights in use. Moreover, as thecircuit of current winding 8 and voltage winding 8 is disconnected fromthe power source 7 as described previously, and gives no influence tothe lighting operation, the direction indicator lights continue to flashto produce an emergency signal, until the last one of the lights finallygoes off.

In the embodiment described above, the contact 5 driven by the switchactuator 6 has been described as a normally closed contact. However, itmay be a normally open contact. In the latter case, the normally opencontact 5 is closed to turn on the direction indicator lights and, aftera predetermined time, the normally open contact is opened to cause theload detector circuit comprising the current winding 8, voltage winding8 and normally closed contact 9 to effect the normal load detection.

In a second embodiment of the present invention as shown in FIG. 3,numerals 1 to 4 denote automobile direction indicator lights, of which1, 1, 3 are right-hand direction indicator lights and 2, 2', 4 areleft-hand direction indicator lights. Numeral 105 is a normally opencontact driven by a switch actuator 106. The driven-type switch actuator106 shown in FIG. 3 is of the type utilizing the charging anddischarging of a capacitor 107, and comprises voltage windings 108 and109 wound in such a manner that their magnetomotive forces are offset byeach other, a thermistor 110 and a resistor 111. Numeral 12 represents acurrent winding and 13 a voltage winding, these windings 12 and 13 beingwound on a common iron core so that their magnetomotive forces are addedto each other. Numeral 14 denotes a normally closed contact driven bythe windings 12 and 13. The windings l2 and 13 and the normally closedcontact 14 together constitute a load detector 15. Use is further madeof a single-pole double-throw type direction indicator switch 10, adouble-pole single-throw type emergency switch 11, a power sourceterminal 18, a load terminal 19 and a power source 7.

In operation, the direction indicator switch 10 is closed, for example,leftwardly to indicate the leftward turn of the vehicle. It causes acurrent to flow into the voltage winding 108 through the capacitor 107in the switch actuator 106 while causing a current to flow into thevoltage winding 109 through the parallel circuit of thermistor 110 andresistor 111, and thereby the magnetomotive forces of the windings 108and 109 are offset by each other to maintain the normally open contact105 open. On the other hand, in the load detector 15, the normallyclosed contact 14 is opened by the magnetomotive force of the currentwinding 12, and once opened, the contact 14 is maintained open by thesum of the magnetomotive forces of the current winding 12 and voltagewinding 13. This allows only a small current passing through the voltagewindings 108, 109 and simultaneously another small current passingthrough windings 12, 13 to flow into the direction indicator lights 2,2', 4 but none of these lights will be lit. However, as the capacitor107 is gradually charged, the current in the voltage winding 108 isdecreased to break the balance between the magnetomotive forces of thevoltage windings 108 and 109 after a certain time, and the normally opencontact 105 is closed by the magnetomotive force of the voltage winding109. Thereupon a voltage substantially equal to the source voltage isapplied to the left-hand direction indicator lights 2, 2, 4 through thecontact 105 so that these direction indicator lights are lit. Thenormally open contact 105 is maintained closed while the electric chargeof the capacitor 107 is discharged. On the other hand, the load detectoris shortcircuited upon closing of the normally open contact 105 tothereby return the normally closed contact 14 to its closed position.Thereafter, the charging and discharging of the capacitor 107 arerepeated to open and close the normally open contact 105 so as to flashthe left-hand direction indicator lights 2, 2, 4, The thermistor 110 andresistor 111 are used for temperature compensation.

When one of the lefthand direction indicator lights 2, 2', 4 goes off,current flows in the circuit of the current winding 12 and normallyclosed contact 14 of the load detector 15 if the direction indicatorswitch 10 is closed, but the current is reduced by the current of one ofthe direction indicator lights and the current winding 12 fails to openthe normally closed contact 14, which thus remains closed.

Therefore, even if the normally open contact 105 is maintained open, theremaining direction indicator lights remain lit by the current passingthrough the normally closed contact 14 and current winding 12. Thus, thedriver of the vehicle can recognize the failure of one of the directionindicator lights from the fact that an indicator lamp (not shown)located in the vehicle cabin and connected in parallel with thedirection indicator lights remains lit.

Since the circuit of current winding 12 and voltage winding 13 alwaysoperates after the normally open contact is opened or after thedirection indicator lights are lit for a certain time, the temperatureof the filament of the direction indicator lights is already raised whenthe said circuit operates, and the resistance of these lights assumes asubstantially steady-state value. Therefore, a substantiallysteady-state current flows in the current winding 12 from the beginningwithout substantial influence of the surge current flowing just afterthe direction indicator lights are turned on, This ensures the failureof one of the lights to be detected in a threelight type directionindicator device as shown in this embodiment. Although the rush currentof the direction indicator lights flows in the load detector 15 to openthe normally closed contact 14 just after the direction indicator switch10 is closed, no surge current flows in the load detector 15 during thenext opening of the normally open contact 105 because the directionindicator lights are already lit by that time. Therefore, the normallyclosed contact 14 is not opened but remains closed thereafter, and noinconvenience is caused to indicate the failure of one of the lights. inthis case, the fact that the normally closed contact 14 maintains itsclosed position makes it possible to prevent any unnecessary on-offoperation of the switch actuator 106.

It holds true with this embodiment, as with the first embodimentpreviously described, that the failure of one of the direction indicatorlights in a three-light type direction indicator device can be reliablydetected over the theoretically greatest possible range of the sourcevoltage.

Further, where it is necessary to produce an emergency signal to preventany danger from occurring when the vehicle stops due to a breakdown orin a similar case, the emergency switch 11 should be closed to connectall the right-hand and left-hand direction indicator lights with theload terminal 19. In this case, the switch actuator 106 operatesindependently of the magnitude of the load and therefore the directionindicator lights are flashed at a predetermined number of intervalsirrespective of the number of such lights in use.

Moreover, since the switch actuator 106 is connected in parallel withthe normally open contact 105 both during the above-described directionindication and during an emergency, power is supplied from the powersource 7 to the switch actuator 106 when the normally open contact 105is opened, that is, when there is no load. Thus, the capacitor 107 ofthe switch actuator 106 can store no-load voltage of the source voltageand thereby can drive the normally open contact 105 with the maximumvoltage available from the power source 7, resulting in reliableoperation of the device.

lclaim:

1. in a direction indicating and hazard flasher device for automobilescomprising a power source, indicator means including two groups of lamploads for indication of turning directions selectively, a directionindicator switch connected to said indicator means for selectivelyconnecting either group of lamp loads to said power source throughswitching means, and a hazard switch connected to said indicator meansfor simultaneously connecting said two groups of lamp loads to saidpower source through said switching means; the improvement wherein saidswitching means comprises:

a first contact connected between said direction indicator switch andsaid power source,

a switch actuator to be energized from said power source forperiodically actuating said first contact,

a series circuit of a second normally closed contact and a currentwinding,

said series circuit being connected in parallel with said first contactthrough a third normally closed contact which is conversely interlockedwith said hazard switch, and

a voltage winding connected in parallel with said second normally closedcontact,

said current winding being adapted to open said second normally closedcontact only when the current therein is larger than a predeterminedvalue,

and said voltage winding being arranged to hold said second normallyclosed contact in the opened state in cooperation with said currentwinding.

2. In a direction indicating and hazard flasher device for automobilescomprising a power source, indicator means including two groups of lamploads for indication of turning directions selectively, a directionindicator switch connected to said indicator means for selectivelyconnecting either group of lamp loads to said power source throughswitching means, and a hazard switch connected to said indicator meansfor simultaneously connecting said two groups of lamp loads to saidpower source through said switching means; the improvement wherein saidswitching means comprises:

a first contact connected between said direction indicator switch andsaid power source;

a switch actuator connected in parallel with said first contact andperiodically actuating said first contact when energized;

and a load detector comprising a series circuit of a second normallyclosed contact and a current winding,

said series circuit being connected in parallel with said first contactand a voltage winding connected in parallel with said second contact,

said second normally closed contact being opened by said current windingonly when a current larger than a predetermined value is suppliedthereto from said power source and being held in the opened state bysaid current winding in cooperation with said voltage winding.

1. In a direction indicating and hazard flasher device for automobilescomprising a power source, indicator means including two groups of lamploads for indication of turning directions selectively, a directionindicator switch connected to said indicator means for selectivelyconnecting either group of lamp loads to said power source throughswitching means, and a hazard switch connected to said indicator meansfor simultaneously connecting said two groups of lamp loads to saidpower source through said switching means; the improvement wherein saidswitching means comprises: a first contact connected between saiddirection indicator switch and said power source, a switch actuator tobe energized from said power source for periodically actuating saidfirst contact, a series circuit of a second normally closed contact anda current winding, said series circuit being connected in parallel withsaid first contact through a third normally closed contact which isconversely interlocked with said hazard switch, and a voltage windingconnected in parallel with said second normally closed contact, saidcurrent winding being adapted to open said second normally closedcontact only when the current therein is larger than a predeterminedvalue, and said voltage winding being arranged to hold said secondnormally closed contact in the opened state in cooperation with saidcurrent winding.
 2. In a direction indicating and hazard flasher devicefor automobiles comprising a power source, indicator means including twogroups of lamp loads for indication of turning directions selectively, adirection indicator switch connected to said indicator means forselectively connecting either group of lamp loads to said power sourcethrough switching means, and a hazard switch connected to said indicatormeans for simultaneously connecting said two groups of lamp loads tosaid power source through said switching means; the improvement whereinsaid switching means comprises: a first contact connected between saiddirection indIcator switch and said power source; a switch actuatorconnected in parallel with said first contact and periodically actuatingsaid first contact when energized; and a load detector comprising aseries circuit of a second normally closed contact and a currentwinding, said series circuit being connected in parallel with said firstcontact and a voltage winding connected in parallel with said secondcontact, said second normally closed contact being opened by saidcurrent winding only when a current larger than a predetermined value issupplied thereto from said power source and being held in the openedstate by said current winding in cooperation with said voltage winding.